Battery powered elevator systems employ a battery as a power source to an elevator machine that imparts motion to the elevator car. A drive unit containing an inverter is typically connected between the battery and the machine. In motoring mode, the inverter converts DC power from the battery to AC drive signals for the machine. In regenerative mode, the inverter converts AC power from the machine to DC power for charging the battery.
Existing elevator systems employ a braking resistor and braking relay to connect the braking resistor across the inverter to provide braking to the machine. The braking resistor and braking relay add cost and complexity to the elevator system.